1. Field of the Invention
The present invention relates to an ultrasonic vibrator for providing ultrasonic waves to a chemical liquid, an ultrasonic cleaning nozzle and an ultrasonic cleaning device to which the ultrasonic vibrator is applied, a substrate treatment device and a substrate treatment system for performing a cleaning treatment on a thin plate type substrate (hereinafter referred to as a "substrate") such as a semiconductor substrate or a liquid crystal glass substrate through the ultrasonic cleaning nozzle. The invention is also related to a method of manufacturing the ultrasonic vibrator.
2. Description of the Background Art
In general, ultrasonic cleaning is known to be a cleaning technique for quickly and reliably removing contaminants adhering to a surface of a cleaned object. While a number of techniques are known for this type of ultrasonic cleaning, a broadly accepted ultrasonic cleaning device includes an ultrasonic vibrator which is set into a cleaning reservoir, having a cleaning solution therein, for irradiating the cleaning solution with ultrasonic waves or the like. The advantage of the ultrasonic cleaning resides in that it is possible to readily and quickly clean a cleaned object having a complicated shape by simply dipping the same in the cleaning solution.
The aforementioned substrate may be assembled into a product through various treatments, where a cleaning treatment for removing particles or the like adhering to the substrate surface is one of the more important steps among the treatment steps. Known devices for performing cleaning treatments for substrates are batch type cleaning devices for simultaneously cleaning plurality of substrates and sheet-fed type cleaning devices for successively cleaning a single substrate.
The ultrasonic cleaning technique may be employed by these substrate cleaning devices for effective cleaning. In case of applying to the ultrasonic cleaning technique is used in the batch type cleaning device, an ultrasonic vibrator is mounted on a cleaning reservoir as described above. However, when the ultrasonic cleaning technique is used in the sheet-fed type cleaning device, an ultrasonic cleaning nozzle having an ultrasonic vibrator therein is used for applying the ultrasonic cleaning. This ultrasonic cleaning nozzle is adapted to irradiate a cleaning solution flowing therein with ultrasonic waves and spray the cleaning solutions onto the substrate.
Known cleaning solutions employed for the aforementioned cleaning of substrates include various chemical liquids in addition to de-ionized water. When a chemical liquid is used as a cleaning solution, various problems arise. While the ultrasonic cleaning nozzle is usually prepared by combining a metal material with resin, the metal material is inferior in corrosion resistance against the chemical liquid and an eluted metal contaminates the substrate. The metal portion of the cleaning nozzle, however, is hardly deformed by ultrasonic vibration and has sufficient resistance against the ultrasonic vibration. On the other hand, the resin portion of the nozzle generates heat or is deformed by ultrasonic vibration, while the resin is excellent in corrosion resistance against the chemical liquid.
When certain ceramic materials are used for the ultrasonic cleaning nozzle, impurities contained in the ceramics are eluted by the chemical liquid and contaminate the substrate. Therefore, neither metal, resin nor certain ceramics are desirable for use as an ultrasonic cleaning nozzle.
In the batch type cleaning device, similar problems arise and, hence, the treatment must be performed by providing an inner reservoir filled with the chemical liquid. The ultrasonic vibrator is disposed inside the reservoir thereby reducing the efficiency of the cleaning treatment due to the damping of the ultrasonic waves by the inner reservoir.